"I'm very worried about that notion of the NDP and the Liberals getting together."

That's Ontario Progressive Conservative Leader Tim Hudak responding to the possibility of a coalition government -- and yes, he should be worried. It could finish him.

Hudak explained that what he is worried about is taxes and spending will go up, but a coalition could see him on the sidelines for another two years, or possibly permanently.

NDP Leader Andrea Horwath jump-started the debate this week with her answer on whether she would rule out a coalition.

"My preference is to sit down with whomever it is that's elected and get some things done for Ontarians," she said. "I'm not overly interested in the details of what that looks like in terms of structure, but certainly I'm interested in getting some things done. I don't think you have to have necessarily a structure to do that ... you just need goodwill."

When a politician doesn't categorically rule out a scenario, it's a possibility, and Horwath would know that. The two leading candidates for the Liberal leadership -- Kathleen Wynne and Sandra Pupatello -- have used muddled wording that also doesn't categorically rule out a coalition, although Pupatello appears to be less inclined.

Coalitions can include members of the opposition in the larger party's cabinet, or they can jointly set a legislative agenda and agree not to pull the trigger on an election for a certain amount of time.

The latter is what happened in 1985, when David Peterson's Liberals and Bob Rae's NDP teamed up to end 40 years of Tory rule. They did not form a coalition, but they did sign an accord that saw several NDP policies passed, while both parties agreed not to force an election for two years. That minority government worked fairly well, and Peterson won a majority government in the election that followed in 1987.

Debate about the virtue of a coalition stirred in the spring after a vitriolic legislative session and a disputed budget agreement between Horwath and Premier Dalton McGuinty that left the province teetering on the edge of an election just months after the Liberals won their minority. But the atmosphere became embittered -- even between McGuinty and Horwath -- so a coalition was a no-go. A new Liberal leader may change that.

Ontario's history is one of left-wing support. The combined popular vote for the Liberals and the NDP was 60% in 2011, 59% in 2007 and 61% in 2003. Even in the Mike Harris years, the combined opposition won 51.7% of the vote in 1995 and 52.5% in 1999.

Typically, a party that wins about 40% picks up a majority of seats, but that doesn't look like it's going to happen if there's an election in the spring, as many predict.

A Forum Research poll released in late December had Hudak's Tories in the lead at 33%, despite a leaderless and unpopular Liberal government. The NDP was at 31% and the Liberals were at 27%.

Hudak may well have moved too far right with his proposal to essentially turn Ontario into a right-to-work province that would crush unions.

Whoever wins the Liberal leadership might not even go to the polls. The new leader could strike a deal with the NDP, as McGuinty did, or a more formal deal as Peterson did, and govern for a couple of more years, arguing that Hudak's policies are too extreme. They could try to ride it out until the economy turns around and the debt is trending downward -- granted, that's a leap of faith with a Liberal-NDP coalition -- leaving Hudak and his party frustrated.